console.log(`typeof undefinee: ${typeof undefined}`); // typeof undefinee: undefined
console.log(`typeof null: ${typeof null}`); // typeof null: object
console.log(`typeof true: ${typeof true}`); // typeof true: boolean
console.log(`typeof NaN: ${typeof NaN}`); // typeof NaN: number
console.log(`typeof BigInt: ${typeof BigInt(1)}`); // typeof BigInt: bigint
console.log(`typeof string: ${typeof "xxx"}`); // typeof string: string
console.log(`typeof symbol: ${typeof Symbol()}`); // typeof symbol: symbol
console.log(`typeof function: ${typeof (() => 123)}`); // typeof function: function
console.log(`typeof 非函数对象: ${typeof {}}`); // typeof 非函数对象: object
console.log(`typeof 数组: ${typeof []}`); // typeof 数组: object
